The present inventor is the inventor in U.S. Pat. No. 4,337,322, issued June 29, 1982. In that patent, there is disclosed a tire filling composition which includes asbestos fiber, ethylene glycol monomer, polyethylene glycol, polyisoprene, process oil (normally a vegetable oil), detergent, sodium bicarbonate, and water. Continuing tests of tire filling and sealing compositions have revealed, however, that certain modifications to the original formulation provide a more effective sealant, and provide better balancing (especially for automobile tires) and better heat transfer characteristics so as to keep tires operating at a lower temperature after they have been driven for a while. Indeed, the composition of the previous patent has been extensively modified, to the effect that polyethylene glycol is no longer used, nor is polyisoprene; a hydrocarbon process oil is now included in the composition; an industrial grade detergent as a wetting agent and emulsifier is now used; and a thickener and binding agent is added.
Accordingly, the present invention provides a composition which includes ethylene glycol, a thickener and binding agent, asbestos fiber, hydrocarbon process oil, an industrial grade detergent as a wetting agent and emulsifier, sodium bicarbonate, and water.
An improved process for manufacturing the tire sealant composition is provided by the present invention, whereby the pH, specific gravity, and viscosity of the finished product--which is batch mixed--may be closely controlled and adjusted as necessary and so as to meet certain specific requirements for use of the tire sealant composition in various types of circumstances.
For example, it is desired that the tire sealant composition of the present invention always have a specific gravity of from about 1.1 to about 1.4, that it have a pH in the range of 8.0 to 9.0; and that the viscosity may be such that it can be easily measured using a funnel as a viscosity measuring tool (as described hereafter) where the viscosity may be consistent from batch to batch or may be varied by the addition of more or less of certain of the constituents. For example, when the product is to be injected into truck tires or off-road tires for such as earth moving equipment, it may have a higher viscosity than when it is intended for injection into automobile tires.
It has been found that suppliers of asbestos fiber will provide what is known as "wet pack" industrial grade asbestos, which may be easily and safely handled; but the present invention also contemplates that the asbestos fibers may be pre-wetted by admixing them with water in small quantities so as to make the fibers easily handled. Wet pack or wet mixed asbestos fiber, however, may appear to be substantially dry to the touch.
The purposes, safety aspects, and advantages of the use of tire sealant compositions are discussed at some length in the inventor's previous United States patent noted above. However, the following discussion will provide observations of tests made by an independent testing authority of compositions according to the present invention, which clearly demonstrate the superiority of the present composition and its better fulfillment of the purposes that have previously been set forth.